Aortic Aneurysms & Dissection Robbins

Aneurysm-localized dilation of a blood vessel True aneurysm: bounded by generally complete but often atentuated arterial wall False aneurysm=extravascular hematoma that communicates with the intravascular space

Types of aneurysms Berry Aneurysm-congenital defect in vessel wall Mycotic aneurysm-infection that weakens the wall Saccular: spherical-5 to 20 cm and partially filled with a thrombus Fusiform: gradual, progressive dilation of the complete circumference

Aortic Aneurysms Atherosclerotic Abdominal aorta Syphilis Ascending aorta and root of aortic valve Dissecting (not a true aneurysm but better thought of as a dissecting hematoma) Blood enters wall of aorta Hypertension, Marfan’s syndrome

Abdominal Aortic Aneurysm Atherosclerotic Below the renal arteries Large thrombus Many associated with dense inflammation Rupture Occlusion of a branch vessel Embolism from atheroma Impingement of an adjacent structure

Abdominal aneurysm

Abd. Aneurysm with laminated thrombus

Early AAA

Aneurysm repair

AAA repair-- 6 months

Aortic Dissection - Dissecting Hematoma Dissection of blood between the media forming a channel within the aortic wall Men 40 to 60 years of age with hypertension Younger group with Marfan syndrome

Aortic Dissection Intimal tear within 10 cm of the aortic valve May have another intimal tear where channel reenters the main aortic channel Ruptures into pericardial, pleural or peritoneal cavities Cystic medial degeneration- break down of elastic fibers

Dissection plane-false lumen Aortic valve Ascending aorta

Dissecting aneurysm Dissection plane

Dissecting hematoma of aorta lumen Hematoma-- false lumen

Dissecting aneurysm True lumen Dissection- false lumen

Normal aorta Cystic medial necrosis

Aortic Dissection Sudden onset of excruciating pain, anterior chest, radiating to the back and moving downward Can be confused with MI Transesophageal echo, CT scan Surgical repair

Types of dissections

DeBakey Classification What determines type? Site of the intimal tear, NOT the extent of the false lumen Either at the: sinotubular junction just past L subclav art

Further Imaging: CT vs Aortography CT, MRIAortography real size of aneurysm assessment of aorta prox & relation to adj structures distal to aneurysm

Treatment Indications for surgical treatment all symptomatic patients twice the normal size of the aorta or 7 cm. progressive enlargement Medical management Beta blockers Control HTN and COPD

Annulo-Aortic Ectasia Aneurysmal dilation of sinuses of Valsalva (Marfan, cystic medial necrosis) Etiology: intrinsic connective tissue defects involve all layers non-specific medial necrosis in non-Marfan patients aortic annular dilatation causes aortic regurgitation Natural history: Marfan’s (Ehlers-Danlos): 45 yo 90% CV deaths, 3/4 of these dissection or rupture

Diagnosis Most are asymptomatic Symptoms/signs of AI bounding pulses widen pulse pressures Marfan syndrome stigmata ectopia lentis (87%) arachnodactyly (77%) MV prolapse (90%)

Surgical Rx - signs of AI - Acute or Chronic Dissection - Rupture - progressive enlargement - Marfan's pt. with size > 5 cm

Surgical Results: Thoracic Aneurysms & Annulo-aortic Ectasia Hospital death - bleeding, neuro, MI Ascending Aorta 4-10% Arch 5-50% Descending 5-15% Thoracoabdominal up to 50% postop 5YSR Ascending 74%Descending 56%

FALSE LUMEN extension related to velocity of ejection and (dp/dt) may rupture pericardium, pleura may occlude branches may re-enter thru a second tear remains patent, dilates

Treatment - Ascending Aorta Types I, II Immediate operation is indicated because rupture likely 1-2% mortality per hour during first 48 hrs Contraindications: advanced age, incurable coexisting disease, paraplegia Note: new stroke may resolve, not a contraindication OPERATIVE STRATEGY: Eliminate INTIMAL TEAR Replace ascending aorta, repair or replace aortic valve Replace arch if false channel leaking or site of tear

Aortic Tear/Transection 15% of blunt chest trauma deaths 90% die at the scene 10% (survivors) false aneurysm without intervention 50% will die within 48 hrs. 15% of blunt chest trauma deaths 90% die at the scene 10% (survivors) false aneurysm without intervention 50% will die within 48 hrs. 90% occur at the aortic isthmus

Repair of Aortic Tear/Transection Operation: Graft replacement via left thoracotomy with partial pump bypass (to perfuse spinal cord) Results 15-30% mortality 7% paralysis 15% can be repaired primarily Operation: Graft replacement via left thoracotomy with partial pump bypass (to perfuse spinal cord) Results 15-30% mortality 7% paralysis 15% can be repaired primarily

Pathology determines treatment Aneurysm (true)DissectionTransection

Let’s Summarize Thoracic Aortic Aneurysm all layers dilated replace the dilated part Annulo-aortic Ectasia all layers dilated; involves aortic root replace dilated part/ replace or repair aortic valve Aortic Dissection tear in intima; false lumen travels varying distances replace part with intimal tear; follow false lumen long-term Traumatic Aortic Transection near-circumferential disruption of all layers; survive if adventia holds graft doesn’t “replace”, it joins the 2 ends together